In thick-film circuitry, conductor strips are formed on a substrate surface from electrically conductive pastes or inks usually applied by screen printing. The substrate so coated is then subjected to a heat treatment designed to dry the applied mass and to facilitate its juxtaposition with similar substrates. In many instances it is necessary to coat both surfaces of a substrate in this manner and to provide conductive connections between aligned circuit points thereof. One possible way is to drive a metallic staple through the substrate in contact with opposite patches of conductive material; this procedure is cumbersome especially when a large number of connections are to be made. Another possibility is to provide the substrate with a bore in line with the circuit points to be interconnected and to contact these points by the heads of a metallic rivet inserted into that bore; this creates difficulties where, because of space limitations, the diameter of the bore must be very small.
A simpler and more convenient solution is to fill such a bore with conductive ink and let it dry. The conductive plugs so formed, however, do not establish a reliable connection since they tend to shrink during the heat treatment which may cause them to rupture in the middle or to break away from one or the other conductor strip to be contacted thereby.